The inner plexiform layer (IPL) of cat retina can be subdivided into sublamina a, the 1/3 near the amacrine cells, and sublamina b, the 2/3 stretching to the ganglion cells, on the basis of differential branching of axons of bipolars and dendrites of ganglion and amacrine cells. The neurons making connection in sublamina a carry OFF center or darkness information and those making connections in sublamina b carry lightness or ON center information. Thus ON and OFF channels remain segregated and parallel in the retina through the higher visual centers. BIBLIOGRAPHIC REFERENCES: Kolb, H.: The orgnization of the outer plexiform layer in the retina of the cat: Electron microscopic observations. J. Neurocytol. 6: 131-153, 1977. Kolb, H. and West, R.: Synaptic connections of the interplexiform cell in the retina of the cat. J. Neurocytol. 6: 155-170, 1977.